1 files changed, 270 insertions, 0 deletions

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644
index 000000000000..eb81556107fe
--- /dev/null
+++ b/kernel/trace/trace_printk.c
@@ -0,0 +1,270 @@
+/*
+ * trace binary printk
+ *
+ * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ */
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/marker.h>
+#include <linux/mutex.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+
+#include "trace.h"
+
+#ifdef CONFIG_MODULES
+
+/*
+ * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
+ * which are queued on trace_bprintk_fmt_list.
+ */
+static LIST_HEAD(trace_bprintk_fmt_list);
+
+/* serialize accesses to trace_bprintk_fmt_list */
+static DEFINE_MUTEX(btrace_mutex);
+
+struct trace_bprintk_fmt {
+        struct list_head list;
+        char fmt[0];
+};
+
+static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
+{
+        struct trace_bprintk_fmt *pos;
+        list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
+                if (!strcmp(pos->fmt, fmt))
+                        return pos;
+        }
+        return NULL;
+}
+
+static
+void hold_module_trace_bprintk_format(const char **start, const char **end)
+{
+        const char **iter;
+
+        mutex_lock(&btrace_mutex);
+        for (iter = start; iter < end; iter++) {
+                struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
+                if (tb_fmt) {
+                        *iter = tb_fmt->fmt;
+                        continue;
+                }
+
+                tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt)
+                                + strlen(*iter) + 1, GFP_KERNEL);
+                if (tb_fmt) {
+                        list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
+                        strcpy(tb_fmt->fmt, *iter);
+                        *iter = tb_fmt->fmt;
+                } else
+                        *iter = NULL;
+        }
+        mutex_unlock(&btrace_mutex);
+}
+
+static int module_trace_bprintk_format_notify(struct notifier_block *self,
+                unsigned long val, void *data)
+{
+        struct module *mod = data;
+        if (mod->num_trace_bprintk_fmt) {
+                const char **start = mod->trace_bprintk_fmt_start;
+                const char **end = start + mod->num_trace_bprintk_fmt;
+
+                if (val == MODULE_STATE_COMING)
+                        hold_module_trace_bprintk_format(start, end);
+        }
+        return 0;
+}
+
+#else /* !CONFIG_MODULES */
+__init static int
+module_trace_bprintk_format_notify(struct notifier_block *self,
+                unsigned long val, void *data)
+{
+        return 0;
+}
+#endif /* CONFIG_MODULES */
+
+
+__initdata_or_module static
+struct notifier_block module_trace_bprintk_format_nb = {
+        .notifier_call = module_trace_bprintk_format_notify,
+};
+
+int __trace_bprintk(unsigned long ip, const char *fmt, ...)
+ {
+        int ret;
+        va_list ap;
+
+        if (unlikely(!fmt))
+                return 0;
+
+        if (!(trace_flags & TRACE_ITER_PRINTK))
+                return 0;
+
+        va_start(ap, fmt);
+        ret = trace_vbprintk(ip, fmt, ap);
+        va_end(ap);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_bprintk);
+
+int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap)
+ {
+        if (unlikely(!fmt))
+                return 0;
+
+        if (!(trace_flags & TRACE_ITER_PRINTK))
+                return 0;
+
+        return trace_vbprintk(ip, fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vbprintk);
+
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+{
+        int ret;
+        va_list ap;
+
+        if (!(trace_flags & TRACE_ITER_PRINTK))
+                return 0;
+
+        va_start(ap, fmt);
+        ret = trace_vprintk(ip, fmt, ap);
+        va_end(ap);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_printk);
+
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+{
+        if (!(trace_flags & TRACE_ITER_PRINTK))
+                return 0;
+
+        return trace_vprintk(ip, fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        const char **fmt = m->private;
+        const char **next = fmt;
+
+        (*pos)++;
+
+        if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt)
+                return NULL;
+
+        next = fmt;
+        m->private = ++next;
+
+        return fmt;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+        return t_next(m, NULL, pos);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+        const char **fmt = v;
+        const char *str = *fmt;
+        int i;
+
+        seq_printf(m, "0x%lx : \"", (unsigned long)fmt);
+
+        /*
+         * Tabs and new lines need to be converted.
+         */
+        for (i = 0; str[i]; i++) {
+                switch (str[i]) {
+                case '\n':
+                        seq_puts(m, "\\n");
+                        break;
+                case '\t':
+                        seq_puts(m, "\\t");
+                        break;
+                case '\\':
+                        seq_puts(m, "\\");
+                        break;
+                case '"':
+                        seq_puts(m, "\\\"");
+                        break;
+                default:
+                        seq_putc(m, str[i]);
+                }
+        }
+        seq_puts(m, "\"\n");
+
+        return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+}
+
+static const struct seq_operations show_format_seq_ops = {
+        .start = t_start,
+        .next = t_next,
+        .show = t_show,
+        .stop = t_stop,
+};
+
+static int
+ftrace_formats_open(struct inode *inode, struct file *file)
+{
+        int ret;
+
+        ret = seq_open(file, &show_format_seq_ops);
+        if (!ret) {
+                struct seq_file *m = file->private_data;
+
+                m->private = __start___trace_bprintk_fmt;
+        }
+        return ret;
+}
+
+static const struct file_operations ftrace_formats_fops = {
+        .open = ftrace_formats_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
+static __init int init_trace_printk_function_export(void)
+{
+        struct dentry *d_tracer;
+        struct dentry *entry;
+
+        d_tracer = tracing_init_dentry();
+        if (!d_tracer)
+                return 0;
+
+        entry = debugfs_create_file("printk_formats", 0444, d_tracer,
+                                    NULL, &ftrace_formats_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'printk_formats' entry\n");
+
+        return 0;
+}
+
+fs_initcall(init_trace_printk_function_export);
+
+static __init int init_trace_printk(void)
+{
+        return register_module_notifier(&module_trace_bprintk_format_nb);
+}
+
+early_initcall(init_trace_printk);